Some of the personnel data stolen in the massive new federal hack predates the widespread use of computers—and hackers themselves. Reuters reports that the breach at the Office of Personnel Management involves security clearances and background checks dating back to 1985. That would explain that while 4 million people were affected, only about half of them are current federal employees. US authorities continue to blame China for the hack.
"This means that they potentially have information about retirees, and they could know what they did after leaving government," says a defense official. He adds that the hackers could use the stolen information, including birth dates and Social Security numbers, to figure out passwords for other sites, including those involved with weapons systems. (Previous stories suggested that China is trying to build databases on Americans.)